Kids can be big business -- particularly when it comes to keeping them in shape. From sports clubs to dance classes to mobile activity groups, the children's fitness franchises that made Entrepreneur's Franchise 500 list this year all are capitalizing in their own unique ways on this burgeoning market. One even targets mothers who need a little exercise themselves. Here's a look at the top ten children's fitness franchises.

No. 1: i9 Sports

At Brandon, Fla.-based i9 Sports, the primary goal isn't to churn out future pro athletes who are obsessed only with winning. It's about having fun. The business was founded by Frank V. Fiume, Jr., in 2002. Franchisees of this business operate local youth sports leagues, tournaments, camps, clinics and special events. Sports include flag football, basketball, soccer, lacrosse and baseball/softball.

No. 2: Gymboree Play & Music

San Francisco mother Joan Barnes created the Gymboree Play and Music program in 1976 when she couldn't find a safe place for new parents and children to play and exercise together. Today, there are locations across the U.S. and throughout the world. Gymboree Play and Music centers offer weekly classes for children ranging from newborn through 4 years old. Its classes are designed to stimulate the senses and encourage children's development.

No. 3: The Little Gym

After teaching grade school in public schools for several years, Robin Wes used his physical education, psychology and motor development degrees to open The Little Gym in 1976. Although it started with a focus on physical education, the program has expanded to include children's intellectual and social development as well. The Little Gym offers programs for various age levels, including Developmental Gymnastics, Karate and Sports Skills Development. Franchises also host birthday parties, summer camps and creative crafts adventures.

No. 4: TGA Premier Junior Golf

Golf isn't only for adults, and TGA Premier Junior Golf has set out to prove it. TGA launched its first 1CGolf Enrichment Programs 1D at six Los Angeles schools in the fall of 2003. As word about the programs spread and the company received more inquiries, TGA expanded to many other Los Angeles-area schools to accommodate the demand. After two years, TGA began franchising throughout the U.S. in 2005. Its programs include lessons, camps and tournaments.

No. 5: JumpBunch Inc.

Founder Tom Bunchman started out as a franchisee himself, having managed and maintained a business for over a decade before launching the JumpBunch concept in 1997. In his kid-focused venture, which brings a new sports-related activity to a child's school or daycare each week, he leveraged his previous franchise experience to expand JumpBunch nationwide, and later internationally. Bunchman and his team select and train local owners with the goal of positively influencing children through sports.

No. 6: Fun Bus Fitness Fun on Wheels

This Tinton Falls, N.J.-based company was founded by mother-daughter team Dawn McGarry and Kari Denton. One armed with a background in business and the other in teaching, they wanted to create a way for kids-- ages 6 months to 13 -- to have fun while staying fit. Enter Fun Bus Fitness Fun on Wheels. But the real kicker is how the businesses get around -- in colorful school buses whose seats have been replaced with padded floors and walls for a unique play environment.

No. 7: My Gym Children's Fitness Center

My Gym was founded in 1983 when partners Yacov and Susie Sherman and Bill Caplin opened their first centers in Van Nuys and Santa Monica, California. The business offers tumbling and exercise classes for children between the ages of 3 months to 9 years. The classes incorporate music, dance, relays, games, gymnastics and sports. My Gym has more than 200 locations throughout the U.S. and abroad.

No. 8: Stretch-N-Grow Int'l. Inc.

After finding out she was pregnant, fitness enthusiast Jill Manly began focusing her attention to infant and early childhood fitness. Through her research, she was surprised to find the lack of fitness in young children. She developed a curriculum for fitness classes, and in 1992 launched Stretch-n-Grow in Galveston, Texas. Each class includes 30 minutes of exercise and 15 minutes of discussion. Classes are taught in many facilities, including child-care and recreation centers, elementary schools and YMCA/YWCA centers.

No. 9: Stroller Strides LLC

Even though Lisa Druxman had worked in the fitness industry since 1990 as a group exercise instructor, personal trainer and health club manager, she couldn't seem to find the time to exercise after the birth of her son. Realizing that other moms were faced with the same challenge, she developed a fitness regimen centered on being outside with your toddler. San Marcos, Calif.-based Stroller Strides was born, and now moms across the country hit the streets to get fit with their strollers in tow.

No. 10: Kinderdance Int'l. Inc.

When founder Carol Kay Harsell's dance studio tripled in size in a matter of months, she wondered why her preschool dance program enrollment wasn't growing, too. Harsell soon realized that her potential clients were enrolled in child-care centers and preschools instead. Deciding to take the program directly to the children at those facilities, she launched Kinderdance International. Within six months, she was offering on-site instruction to more than 30 child-care centers in the Phoenix area. Today, there are more than 100 franchises around the U.S. and Canada.